We have determined the DNA sequence of one bacteriophage genome and willdetermine about ten more, and roughly 15 more are available in public databases. We will use PSC facilities to assemble our DNA sequence data to produce finished sequences and then to analyze those sequences. Analysis will include, first, analysis of individual genome sequences to determine the genetic structure of the individual viruses and , second, comparisions among the newly determined sequences and other DNA sequences in the GenBank database In particular, we will focus on comparisons between related bacteriophage sequences, at the level of individual genes and proteins and at the level of the entire genomes. Information from these comparisons will address issues of structure/function relationships in the viral proteins and of genetic mechanisms operating in the evolution of viral genomes.